Fractionating tower



Feb. 2 1926. 1,571,805 F. B. SAMUEL FRACTIONATING TOWER Filed Apr-11,171924 3 Sheets-Sheet l i mmg ggnumu Ill! )1; v I @I" i 1 l; 1 1 1 Feb. 21926.

- F. B. SAMUEL FRACTIONATING TOWER 3 Sheets-Sheet 2 Filed April 1'7,1924 Feb. 2 I926 1,571,805

F. B. SAMUEL FRACTIONATING TOWER Filed April 17, 1924 5 Sheets-Sheet 5Patented Feb. 2, 1926.

uairso STATES PATENT QFFICE.

FRANK BERNETTE SAMUEL, OF BATON ROUGE, LOUISIANA.

FRACTIONATING TOWER.

Application filed. April 17, 1924. Serial No. 707,193.

The present invention relates to an im- 1 proved condensing andfractionating tower for use in treating oil vapors as well as for use intreating any and all other vapors to which the fractionating process maybe applied.

An object of this invention is to provide a tower permitting the slowcooling, by air and partial condensation, of oil vapors during theirpassage from the still to the condenser, and a tower which may be usedas an intermediate cooling, fractionating and partial condensing devicefor the vapors so that when the vapors are delivered to the finalcondenser complete condensation may take place.

Another object is to provide a tower which may serve as an intermediatedevice, either singly or in multiple, of the above character and whichallows the separate fractions of the vapor to condense out with theheavier fractions condensing first, and then the ighter ones following,the lightest fractions being allowed to pass to the light productcondensing; worm, and the heavy and intermediate products may be runback to the still or to cooling coils or to such point as desired by therefiner.

A further object is to provide a tower or series of towers wherein thevapors 'may traverse a long path with a slow temperature drop to insurethat the condensation products become more uniform in character, and maybe more readily separated.

A still further object of the invention is to provide a tower which maybe arranged in series with a number of like towers oetween the still andfinal condenser, and which when so arranged allows each tower to retainonly its own condensate and not be contaminated with any of thatentrained from a preceding gower and which insures from tower to towerand to the final condenser. The nature of this condensate may then bepredetermined and obtained by means of draft control.

Another object is to provide a tower which when arranged in series withother similar towers makes it possible to remove from the mixed vaporsseveral simultaneous cuts or fractions, each'cut in itself being aperfectly separated fraction. The fractionating efficiency of the towerbeing such, rerunning of these products becomes unnecessary.

A further object is to provide a tower, serving either singly or inmultiple, whose cooling effect can be so controlled that only thefraction or fractions desired will be condensed, and only thosefractions returned to the still that will be improved by furtherdistillation. In the case of an oil vapor, only the heavy fractions willbe returned to the still in order that they may be later partly crackedby the high temperatures found near the end of the run with theformation of lighter fractions of a lower gravity.

A further object of the invention is to provide atower which efiectsmaximum efficiency of fractional condensation without the aid of refluxaction or refractionation (with stones or the like), the tower actingstrictly as a fractional condenser. The condensate formed is removedfrom the condensing zones as quickly as possible.

A further object is to provide a tower which may serve either singly orin multiple wherein the fractionating efiicienoy of the towers and thefuel consumption of the still, because of said towers, remains constantregardless of the varying weather conditions and seasonal changes.

Another object of the invention is to provide a tower which whenarranged singly or in multiple has the tendency to keep all of its tubecondensing surfaces clean by the scouring eifect of the vapors, "as theysweep downward in the tubes carrying with them the forming condensate.The tendency of the condensate then to form contaminating deposits onthe condensing tube surfaces, as experienced in towers usin reflux wherethere is a partial suspension of the condensate in the refluxing tubes,is then avoided.

A still further object of the invention is to provide a tower in whichthe products of condensation are uniform in character, Ann +n flan Fnnt'that nanln nnnr ln'nninn" h'll'm is exposed to the exact same conditionsof cooling so as to make each tube produce a condensate of exact samecharacter as any other tube within the same tower.

With the foregoing and other objects in view, the invention will be morefully de' scribed hereinafter, and will be more particularly pointed outin the claims appended hereto.

In the drawings, wherein like symbols rcler to like or correspondingparts throughout the several views,

Figure 1 is a side elevation of a portion of a condensing andfractionating plant disclosing a series of towers constructed ac cordingto the present invention.

Figure 2 is an enlarged side elevation of a tower constructed accordingto the present invention, the view being taken at right angles to theshowing in Figure 1 and parts being broken away to disclose the interiorstructure.

Figure 3 is a rertiial section taken axially through the towersubstantially on the line 3-3 of Figure 2.

Figure l is a transverse section taken through the tower near its upperend, substantially on the line l--l of Figure 2.

Figure 5 is a similar view taken below the section of Figure l andsubstantially on the line 5 5 of Figure 2, and

Figure 6 is a transverse section through the lower end ol the towertaken substantially on the line G6 of Figure 2.

lle'tcrring to the drawings the tower comprises a body portion or casing10, the outer wall oil which may be of composite structure including ametal shell 10 and an outer coating of insulation or the liker10" andthe body 10 is of suitable height to provide the necessary verticaldistance for carrying out the objects and advantages of the tower. Thetower '10 is provided at its up per end with a horizontal partition 11which constitutes a header for a plurality of tubes 1:2 which arearranged in upright position within the tower, but which converge tr*ard their lower ends and are secured in a lower partition or header 13which is secured in the tower 10 in spaced relation From the lower endthereof. The lower end or? the tower ll beneath the header 13 com prisesan expansion chamber lei and a condensate trap. The tower has aninclined bottom 15 forming the lower end of the chamber l-l: and uponwhich may be collected the condensate tor carrying the same oil througha drain pipe 16 which opens through the lowermost portion of the bottomThe tower 10 may have a manhole 17 at one side of the expansionchamberlet for the purpose of gaining access to the interior and bottom of thetower when necessary.

The lower header 13 is provided with a depending circular ballle 18which surrounds the lower ends of the pipes 12 and which extends down toa point past the vapor outlet pipes 19 and which insures the eirculationof the downwardly flowing vapor troin the pipes 12 through thecondensate trap or expansion chamber let to the point past the. vaporoutlets so that the vapor has to revert back v thereby reversing itsdirection of flow, with the result that the en trained condensatebecomes thrown, or literally snapped c t of the vapor before the vaporis permitted to exhaust through the outlet pipes 19 which are connectedthrough one or more sides of the expansion chamber l-l and above thelower edge of the ballle 18 and also well above the bottom of theexpansion chamber 1-1:, being located close to the lower header 13.

The upper header 11 carries an upper stack section or line 20 which isof less diamcter than the tower body 10, and which lies within the areaof the upper ends of the pipes or tubes 12, and which forms with theouter wall an annular chamber 22 opening downwardly through the tubes12. The tower ll") 3 provided in one or more sides with inlet pipes 521.which open into the an nular clnu r 22 for admission of vapor to thechan r. and for the uniform dis tribution oi the apor to thedowi'lwardly extending tubes 12. The lower 10 is pro vided with a cover2?) in the form of a ring which is substantially ol. 'lrusto-conicalform and titted about the line 20 and projecting over the side wall orbody 10 of the tower. This cover 23 is spaced above a top plate 23 whichcloses the top of the chamber 22 so that the vapor cannot rise, andtherefore descends through the tubes 12. The cover plate 2 used andspaced above the top plate or plates 23 to prevent damage and le: kageto the top plate iii-l such as by rain and the like strikii'ig the hottop plate 23 which is likely to cause undue straining thereof. The lineE20 is provided with an insulated damper ill; of: suitable constructionmounted upon a shaft carrying a grooved wheel at over which is trainedan operating chain :27 depr-anding atthe side ot the tower, and thelower end of which is in position of easy access of the operator oratteniilant for regulating the position oil the damper i! l. The d mperchain 527 may also be actuated by an automatic temperature controlregulator so as to bring the operating tower ellicicnry down. to a linepoint. The flue or upper stack .Zl'l is open at its top and is protectedby a series of covers or do doctors 28 for shedding rain and the likeand for promoting an up-dratft through the flue 20.

The tower ll) is provided" iuuuediately above the lower header 1 3 withan annular row of spaced apart air slots or ports in) at suitable heightfor admitting air in the desired quantity to the interior of the towerabove the header and about the lower ends of the tubes 12. The tower 10is also provided with an annular hood or rain guard 30, which is securedto the outer wall of the tower above the slots 29, and which extendsoutwardly from the tower and is supported upon radial braces 31 toprovide sufficient space for access of air to the slots 29, the skirt ofthe hood 30 depending sufficiently to cover the slots 29 and ward offrain and the like liable to enter the slots 29.

A central deflector 32 is mounted in the tower 10 and supported by lowerbraces 33 and upper braces 34 in an intermediate position between theheaders 11 and 13, and preferably near the lower header 13. The centraldeflector 32 is slightly raised from the bottom header 13 in order toinduce a partial central draft. This small central draft causes theinlet cooling air to be drawn in more closely about the foot of thetubes 12 before passing upward. A greater portion of the tube coolingarea is thereby made effective. The deflector 32 is of invertedfrusto-conical form and substantially follows the inclination of thetubes 12, so as to 'divertthe inflowing air toward and about the tubesfor the major portion of their length.

The deflector 32 is spaced at its upper end from the upper header 11 andthe said upper header 11 is provided with a central opening whichregisters with the flue 20 so that the air after passing upwardly aboutthe tubes 12 may then pass upwardly and out through the flue 20. By thisarrangement the tubes 12 are subjected to uniform cooling around theentire circumference of the tower by the upward circulation of the airthrough the tower.

In the operation of thetower the oil vapor is admitted to the towerthrough the inlet pipe 21 and into the annular chamber 22 from which thevapor is distributed to the upper ends of the tubes 12. The vapor thenpasses downwardly through the tubes 12 into the expansion chamber orcondensate trap l and within the area determined by the cir cular bah'le18. The condensate which is carried downwardly through the tubes 12 withthe vapor falls within the expansion chamber.

and is collected upon the inclined bottom 15 and drained off through thepipe 16. It is important that the pipe 16 be of suiiicient diameter toquickly carry off the accumulate-d condensate in order to prevent theundue heating of the expansion chamber 14 and further to reduce to aminimum the tendency of the condensate to form contaminating deposits onthe tower bottom by remaining at this high temperature. The vapor thencirculates about the lower end of the circular ba e 18 and passes upwardthereby reversing its direction of flow. The condensate is hence thrownor literally snapped out of the vapor by this sudden change of directionof the vapor flow. On reaching the outlet pipes 19 the vapor then passesoutwardly in a dry, or condensate free state to the next fractionatingbody or to the condenser, depending on the location of the tower in theseries.

For cooling and condensing the vapor as it passes downwardly through thetubes 12 air is admitted beneath the hood 30 and through the slots 29.The air thus blows directly and uniformly against the lower ends of thepipes 12 around the entire circumference of the tower and is thencedistributed upwardly about the pipes by the central deflector 32 andfills the outer annular portion of the tower 10 so as to cool the pipesor tubes 12 throughout their lengths. The air finally passes upwardlythrough the central portion of the header 11 and into the fine 20 whereit is exhausted through the top of the tower. The height of this flue orstack is determined by the amount of draft required to give thenecessary temperature drop to the vapor to condense the particularfraction sought from that tower. The intensity of this cooling draft isgoverned directly by an insulated damper 24L which controls the amountof cooling air permitted to be passed up through the tower. The damper24 is to be actuated preferably by an automatic temperature controlregulator. With such a de vice together with the insulation about thetower body 10 the amount of cooling desired of each tower can definitelybe maintained regardless of weather conditions or seasonal changes.

As shown in Figure 1, it is preferable to use aplurality of the towers10 in series and between a still 35 and the final condenser not shown.The still is shown diagrammatically and provided with a. dome 36 fromwhich leads one or more pipes 31' connected to the inlet pipes 21 at theupper end of the first of the towers 10. The outlet pipes 19 near thelower ends of the towers 10 are connected by pipes 38 with the inletpipes 21 of the next tower 10. the pipes 38 being inclined upwardly fromthe bottom of one tower to the top of the adjacent tower. In this mannera plurality of towers 10 are connected in series by the pipes 38 asshown. Each tower 10 is provided with a condensate drain 16, at itsbottom so that the condensate may be withdrawn at each stage throughoutthe series. This condensate may be returned to the still or coolingworms or to such points as the refiner desires. The last tower 10 of theseries may have its outlet pipe 19 connected by a pipe 39 to a vaporseparator 40 or other suitable device for further separating the vaporcontents. This separator, however, is only necessary in the event f thecase wherein the tower is desired.

to be driven at a greater rate than that provided originally in thetower design. In such a case the separating efficiency of the. towercondensate trap becoines lowered and incr ased separating capacity isthen re quired to render the same etl'ective separation. The separatorhas an outlet pipe at for the lighter vapor, and a take off pipe 4-2 forthe heavier entrained condensate particles which are delivered from theseparator l0 and which are then united with the si1nilar condensate fromdrain 16 in the final tower.

It is apparent from this construction that each tower is provided with avapor inlet at its upper end and an outlet at its lower end, and aplurality of passages or fines. in the tor-1n of the tubes in thepresent instance. between the inlet and outlet ports through which thevapor is divided into separate streams, and has the means for adniittingand drawing a current of air uniformly inward around the circumferenceof the. tower and passing: 5.11310 upwardly through the tower about theseparate tines or passages for cooling; the vapor and means for carryingoil the air from the top of the tower after the pipes have been cooledand means for controlling the amount of air permitted to be passed inthrough the tower.

It will he noticed in the foregoing; obiests, description and appendedclaims that the vapor flow is downward through the sue cessive towers inthe series. This downward flow is unlike that used in air cooledfractionatine' towers in general. In the upward flow types offractionating tower the condensate formed in the tubes retluxes backand, hence. passes in opposite direction to the vapor tlow. In the downflow type the condensate and vapor pass in the same direc- 'tion.

The refluxing; found in upward tlow, air cooled oil vapor fraetioningtowers has been found to he a de'ided disadvantage instead of an asset,since the condensate formed is always of a darker color and hi ghergravity than the resultant vapor would be on being condensed. The vaporsthen due to their high velocity sweep part of this condensate over intothr next iii-actionatiug' body or to the receivii'ie' house. This.therefore in'iparts to the fractions formed in these bodies a darhcrcolor and higher gravity. or in other words. a poor separation of thefractions is eli'ecied in them. Further. it has been found thatrefluxing); causes deposits to be formed on the condensing surface,since the condensate is held to some extent in the condensing; tubes inpartial suspension. there fore, affording: excellent conditions underwhich these deposits may be formed. The deposits are partly the cause ofthe bad odor found in poorly fractioned light products. The presence ofthese deposits results in increased relining expense in thatconsiderable sweetening is required. Again, heavy refluxing sets up aback pressure n the still. This :auses excessive blowing of the safetyalve. This blowing is dangerous and a loss. Fun ther, to reduce it thefires must be slacked which, therefore, incurs a time loss. Lastly it isfound that when using; reflux action even if the distillation is slowand no entrainment exists, that the condensate found is of no betterquality than that formed in a tower not using the reflux principle, butwhich obtains its objects by a slow and uniform temperature drop, thetower being; strictly a fractiolnil cmulenser.

In the downward flow type of tower, on the other hand, quite aditlicrent set of conditions exist: No condensate is entrained from thetower though the vapor velocity may be extremely high, since the vaporflow is downward and no refluxing exists. The ccndensate formed in thecondensing tubes passes downward with the vapor and snapped out of thevapor in the condensate trap as the vapor reverses its direction of tlowto escape from the tower. Nothing, therefore. but an absolute dry orcondensate tree vapor passes on to the next condensing body or to thereceiving house. Further, the down arrd sweeping action of the vaporstends to scour the condensingtubes, thereby lzee iing them clean andeliminating, therefore, the tendency of condensate to form thecontaminating odor giving deposits. The downward vapor flow furtherreduces the pressure in the still. allowing the still, therefore, to bedriven harder without danger of blowing and consequently allowing ashort time for a run.

At first thought it might be reasoned that by passing the vapor down inthe towers instead of up that one was opposing; the tendency of thevapors to rise. On further reasoning. it will be seen. however. thatwhen the vapors are passed up through a tower they have to pass down thesame distance through a connecting passage in order to enter the nexttower. Hence, there is no difference in. pressure whether it passes upthrough a tower or down. since it mustpass down the same distance itgoes up in both cases. However. by passing; the vapor down throupgh thetower. the v por does not have to buck the talline condensate, asexperienced in the up flow method. This pressure amounts to severalpounds in the lirst tower. A furthi-a' advantage of the downward flowtower is that the vapor and coollug air pass in opposite directions.ounter current cooling with the resultant maximum elliciency of heatexchange is therefore effected.

It will be further noted that the individual towers are insulated with astandard insulation. .Air cooled fractionating towers in general do notemploy any insulating medium; hence, their performance is very orratic.Due to weather conditions ant. seasonal changes the fractionatingefficiency of the tower becomes quite unreliable and the fuelrequirements are found to vary as much as a0 per cent together with atime loss due to slower distillation incurred. The general type of aircooled fractionating towers are not so designed that an insulatingmedium can be profitably employed. The usual draft facilities arelimited and the greater part of the cooling is intended to be done bydirect radiation through the outer shell of the tower. If this typewere, therefore, insulated more towers would be required to accomplishthe same cooling; so that the application of the insulation then becomesuneconomic. The tower described herein is, however, particularly suitedto insulation, since the vapor passes downward and the. cooling air up,counter current cooling with its maximum eliiciency of heat exchange isthereby effected with the result that a minimum amount of cooling air isrequired to obtain the necessary temperature drop. The draft may be madesufficient for the requirements by increasing the stack height. Nocooling by radiation from the tower body is then necessary, since allair for cooling under maximum conditions of draft requirement can betaken through the ports provided. This draft is controlled by a damperand can be regulated by temperature control regulators. Thefractionating efficiency of the tower then becomes independent ofweather conditions and seasonal changes. A uniform fuel consumption isthe net result. The warmer the weather the wider the damper is openedand the colder the weather the smaller the opening allowed. By thiseflicient temperature control and by the use of insulation enormous fuelsaving is effected. On cold .or rainy days the amount of run back froman exposed tower betomes excessive. Excessive run back represents a fuelloss, for it requires additional fuel to send the vapors back into thetowers. By insulating, only the theoretically necessary amount of runback needbe returned to the still. The amount of this can be determinedand obtained by automatic temperature con trol.

The tower expansion chamber or condensate trap is designed to providemaximum efficiency of separation of the vapor and condensate undernormal running conditions of the still. The occasion might arise,however, when the still, either through inattention on the part of theoperator, or for special reasons is driven faster than the ratedcapacity of the tower condensate trap. This forcing of the tower it willbe seen causes an increase of gravity of the vapor finally discharged,since some entrainment exists. The separator, therefore, is installed toeliminate this condensate and insure that only dry or condensate freevapor passes to the final condenser. The height of the stack on thetower has also been made of a slightly greater height than thatrequired-for normal running conditions in order to provide the necessarydraft to cause suflicient cooling of the vapor when the tower issubjected to an overload. The purpose of this is to insure for the:tower a perfect performance under adverse conditions.

It is obvious that various changes and modifications may be made in thedetails of construction and design of the above specifically describedembodiment of this invention without departing from the spirit thereof,such changes and modifications being restricted only by the scope of thefollowing claims.

What is claimed is 1. In a fractionating tower, a vertical, insulated,non-heat radiating body portion having depending fines therein, meansfor directing vapor into the upper ends of said fines, means forcollecting condensate from the lower ends of the flues, means forcarrying oftthe resultant vapor in a dry or condensate free state fromthe lower ends of the fines, means for directing an induced draft of airuniformly upward about said fines for their entire length for coolingand con- (lensing part of the vapor therein, means for preventing lossof heat by radiation through the outer body surface of the tower, andmeans for varying or maintaining any desired temperature drop within thetower irrespective of weather conditions, or seasonal changes.

2. In a fractionating tower, a vertical insulated non-heat radiatingcylindrical body, spaced headers arranged within the body, a pluralityof fines flaring upwardly and secured in an annular area through theupper header and having their lower ends secured through the lowerheader in a central restricted area thereof, means for supplying an oilvapor to the upper ends of the fines, means for directing a draft of airagainst the lower ends of the flues around the entire circumference ofthe tower, a deflector ar ranged between the fines for directing theuniformly admitted current of air upwardly along the fines throughouttheir entire length, means for collecting the condensate beneath thelow-er header, and means for carrying off the remaining vapor issuingfrom the lower ends of said fiues in a dry or condensate free state.

3. In a fractionating tower, a vertical insulated non-heat radiatingcylindrical body, spaced headers arranged in the body, an outlet fiue orstack carried by the upper header and extending through the top of thecylindrical body for carrying off a current of air from beneath theupper header, said body having lateral openings around the entirecircumference of. the lower body immediately above the lower header foruniform ingress of air to the interior of the body, a plurality of finesarranged in circular order within the cylindricalbody and secured atopposite ends through the upper and lower headers and with the lowerends of the flues disposed in 1 restricted central area of the lowerheader, a circular bafl'le depending from the lower header and adaptedto direct vapors downwardly from the ends of the fines and then reversetheir direction of How so as to deposit the condensate in the bottom ofthe tower and a central deflector arranged within the group of fines fordireoting the current of air upwardly and about said flues for theirentire length.

a. In a fractionating tower, a Vertical insulated body portion, spacedheaders in the body portion providingta vapor receii ing;- chamber atthe upper end 01 the towe and an expansion chamber or condensate trap atthe lower end of the tower,tubes arranged vertically in the tower andsecured at their ends in said head for dividing the down flow of "vaporinto a plurality of sepa ate streams, said tower having a plurality ofslots in its side and immediately above the lower header for admittingair to the interior of the tower about said tubes, an annular hoodsecured about the tower and overhanging said slots for deflecting rainand the'like therefron'i, a line opening through the central portion ofthe upper header and projecting upwardly through the tower for carrying;oll' air from between the headers, a damper located in said line forcontrolling volume of incoming cooling air, a circular deflectorarranged betweenthe tubes for deflecting the air against and about thetubes to insure the complete surface contact of the tubes with theupfiowing air current.

FRANK BERNETTE SAMUEL.

